1. Field of the Invention
The present invention relates to a computer program product, system, and method for creating a restore copy from a copy of source data in a repository having source data at different point-in-times and reading data from the repository for the restore copy.
2. Description of the Related Art
In a storage environment, a storage controller may create point-in-time (“PiT”) copies of a production volume using point-in-time copy techniques, such as the IBM FlashCopy® (FlashCopy is a registered trademark of IBM), snapshot, etc. A point-in-time copy replicates data in a manner that appears instantaneous and allows a host to continue accessing the source volume while actual data transfers to the copy volume are deferred to a later time. The PiT copy appears instantaneous because complete is returned to the copy operation in response to generating the relationship data structures without copying the data from the source to the target volumes. PiT copy techniques typically defer the transfer of the data in the source volume at the time the PiT copy relationship was established to the copy target volume until a write operation is requested to that data block on the source volume. Data transfers may also proceed as a background copy process with minimal impact on system performance. The PiT copy relationships that are immediately established in response to the PiT copy command include a bitmap or other data structure indicating the location of blocks in the volume at either the source volume or the copy volume. The PiT copy comprises the combination of the data in the source volume and the data to be overwritten by the updates transferred to the target volume.
When an update to a block in the source volume involved in a PiT copy relationship is received, the copy of the track as of the point-in-time must be copied to side file or the target volume before the new data for the track is written to the source volume, overwriting the point-in-time copy of the data.